Beachball-size balloons descended from the rafters and bounded around the stage Monday at the Vic Theatre, and it threw Jenny Lewis off her game for a minute.

“I’m a professional musician … (but) all these balls are distracting me,” she said with a laugh, as she fumbled the opening of her encore. Lewis is indeed a pro, a one-time child actress who still brings a hint of Hollywood glamour to her show. She’s at ease in front of an audience; confident, stylish, with a knack for selling the songs with a raised fist, twirling wrist or pogo hop. At times, she and her six-piece band came off as slick, especially when they plunged into a half-dozen sleek rock songs from across Lewis' career, including her off-and-on band Rilo Kiley.

Yet her pristine voice, a piercing instrument in the upper register with a timbre reminiscent of a young Emmylou Harris, specializes in dispensing honesty, no matter how discomforting or withering it might be.

Lewis’ music is pretty straightforward, with a premium placed on pop structure and harmony-enriched melody. When there is some swagger, as on the Rilo Kiley porn-industry slapdown “The Moneymaker,” she sounds like she’s sending it up rather than reveling in it. In contrast to the earnestness that pervaded the California singer-songwriter scene for decades, Lewis often displays a wry, even caustic humor that has more in common with Randy Newman and Warren Zevon.

Mostly, she sings deceptively breezy songs about unpleasant subjects: breaking up relationships (“I’m fraudulent, a thief at best”), suffering through vacations from hell (“How can you hear me scream if you still got your headphones on?”), losing her mind (“I put my head underwater baby”).

She dove into a melting pot of California influences: country rock, Laurel Canyon folk, Fleetwood Mac’s glistening guitar melodies. There were a few outliers, notably the stomping, Apocalyptic blues-gospel suite, “The Next Messiah,” the grittiest track she’s ever done. The more conventional pop-rock didn’t do much to distinguish her, but when she stripped things back, the results could be stunning.

After a few false starts amid the balloons, “The Voyager” turned into a poignant meditation on feeling alone and adrift. The closing “Acid Tongue” evoked a country sing-along around an imaginary campfire, with Lewis, her bandmates and members of opening act Nikki Lane’s band. “You know I’m a liar,” they sang, and they made the admission sound beautiful. It felt and sounded as sunny as California, sure, but there was nothing warm or reassuring about it.